MODIFICATION OF COMBUSTOR STOICHIOMETRY DISTRIBUTION FOR REDUCED NOX EMISSION FROM AIRCRAFT ENGINES

Measurements of the emissions from an experimental engine were analyze d to construct a design chart for the reduction of oxides of nitrogen (NO(x)) in conventional combustors. The design chart was used to recon figure the stoichiometry distribution of the combustor of a production engine so as to reduce NO(x) while holding the emissions of carbon mo noxide, unburned hydrocarbons, and smoke well below existing regulatio ns. Combustion section pressure loss and combustor outlet temperature distributions were substantially unchanged. The modified design was re fined with the aid of computational fluid dynamics calculations to opt imize the emissions reduction. Worthwhile reductions in NO(x) were obt ained with combustor modifications that are transparent to the engine user.